Integrated package assembly for switching regulator

ABSTRACT

In one embodiment, an IC package assembly for a switching regulator, can include: a power switch chip including a control electrode and a first electrode on an obverse side and a second electrode on a reverse side, where the second electrode is configured as a switching terminal of a switching regulator; a control chip including a driving electrode and a plurality of input and output electrodes on the obverse side; and a leadframe including an extension pin, a substrate, and a plurality of discrete pins, where the extension pin is formed integrally with the substrate, and where the reverse side of the power switch chip is arranged on the substrate of the leadframe by a conductive material to electrically connect the second electrode to the substrate.

RELATED APPLICATIONS

This application claims the benefit of Chinese Patent Application No.201410036423.9, filed on Jan. 24, 2014, and of Chinese PatentApplication No. 201410035538.6, also filed on Jan. 24, 2014, both ofwhich are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention generally relates to the field of semiconductorpackaging, and more particularly to an integrated circuit packageassembly for a switching regulator.

BACKGROUND

With developments of miniaturization, lightweight, andmulti-functionalization of electronic products, semiconductor packagedensities are further increasing. Both integrated circuit chips, as wellas traditional discrete components (e.g., inductors) and powertransistors can be included in a same semiconductor package. In such anintegrated circuit package, the arrangement and connectivity amongintegrated circuit chips and discrete components are very important tothe overall volume and performance of the integrated circuit package. Intraditional integrated circuit package assembly for switchingregulators, a voltage spike can easily occur on a switching pin of theintegrated circuit package assembly that may interfere with adjacentpins to generate noise. Also, leakage current related failures canoccur, and heat dissipation performance of the switching pin may berelatively poor.

SUMMARY

In one embodiment, an integrated circuit (IC) package assembly for aswitching regulator, can include: (i) a power switch chip including acontrol electrode and a first electrode on an obverse side and a secondelectrode on a reverse side, where the second electrode is configured asa switching terminal of a switching regulator; (ii) a control chipincluding a driving electrode and a plurality of input and outputelectrodes on the obverse side; (iii) a leadframe including an extensionpin, a substrate, and a plurality of discrete pins, where the extensionpin is formed integrally with the substrate, and where the reverse sideof the power switch chip is arranged on the substrate of the leadframeby a conductive material to electrically connect the second electrode tothe substrate; and (iv) the control electrode being electricallyconnected to the driving electrode, and the plurality of input andoutput electrodes of the control chip are electrically connected tocorresponding of the discrete pins.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of an example switching regulator.

FIG. 2 is a diagram of an example integrated circuit package assemblyfor switching regulators.

FIG. 3 is a diagram of a first example of an integrated circuit packageassembly for switching regulators, in accordance with embodiments of thepresent invention.

FIG. 4 is a sectional view diagram of the integrated circuit packageassembly for switching regulators of FIG. 3, in accordance withembodiments of the present invention.

FIG. 5 is a diagram of a second example of an integrated circuit packageassembly for switching regulators, in accordance with embodiments of thepresent invention.

FIG. 6 is a sectional view diagram of the integrated circuit packageassembly for switching regulators of FIG. 5, in accordance withembodiments of the present invention.

FIG. 7 is a diagram of a third example of an integrated circuit packageassembly for switching regulators, in accordance with embodiments of thepresent invention.

FIG. 8 is a sectional view diagram of the integrated circuit packageassembly for switching regulators of FIG. 7, in accordance withembodiments of the present invention.

FIG. 9 is a diagram of a fourth example of an integrated circuit packageassembly for switching regulators, in accordance with embodiments of thepresent invention.

FIG. 10 is a sectional view diagram of the integrated circuit packageassembly for switching regulators of FIG. 9, in accordance withembodiments of the present invention.

DETAILED DESCRIPTION

Reference may now be made in detail to particular embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. While the invention may be described in conjunction with thepreferred embodiments, it may be understood that they are not intendedto limit the invention to these embodiments. On the contrary, theinvention is intended to cover alternatives, modifications andequivalents that may be included within the spirit and scope of theinvention as defined by the appended claims. Furthermore, in thefollowing detailed description of the present invention, numerousspecific details are set forth in order to provide a thoroughunderstanding of the present invention. However, it may be readilyapparent to one skilled in the art that the present invention may bepracticed without these specific details. In other instances, well-knownmethods, procedures, processes, components, structures, and circuitshave not been described in detail so as not to unnecessarily obscureaspects of the present invention.

Referring now to FIG. 1, shown is a schematic block diagram of anexample switching regulator. This example switching regulator caninclude control chip U1, power switch chip Q1, supply terminal VCC,ground terminal GND, current sensing terminal I_(SEN), voltage sensingterminal V_(SEN), and switching terminal SW. Switching terminal SW canbe a common node between a power switch (e.g., Q1) and an inductor(e.g., L) of a power stage of the switching regulator.

Power switch chip Q1 can include a control electrode, a first electrode,and a second electrode. For example, the control electrode of Q1 canconnect to a driving electrode from control chip U1. The secondelectrode can connect to an input voltage, and a first electrode canconnect to ground. The on/off states of power switch (e.g., transistor)chip Q1 may be controlled by a switching control signal from the drivingelectrode of control chip U1, which can connect to the gate oftransistor Q1. Control chip U1 can also include input/output electrodeCS, which can connect to the first electrode (e.g., source or drain) ofpower switch chip Q1. Transistor Q1 can also be coupled to groundthrough control chip U1. The input and output electrodes of control chipU1 can correspondingly be coupled to the input and output terminals.Control chip U1 and power switch chip Q1 can be integrated into a singlepackage 00 to form an integrated circuit (IC) package assembly forswitching regulators.

Referring now to FIG. 2, shown is a diagram of an example integratedcircuit package assembly for switching regulators. This example ICpackage assembly for switching regulators 00 can include power switchchip 01, control chip 02, package encapsulant 03, and a leadframeincluding discrete substrate 04, substrate 05, and a plurality ofdiscrete pins. Power switch chip 01 can be arranged on substrate 04, andcontrol chip 02 can be arranged on substrate 05. Also, a switchingterminal can connect to switching pin SW of the leadframe through abonding wire.

The input and output electrodes of control chip 02 can connect to supplypin VCC, ground pin GND, current sensing pin I_(SEN), and voltagesensing pin V_(SEN) through bonding wires. However, when a spike voltageis generated at switching pin SW, adjacent pins can be interfered withto generate noise. Also, the space among switching pin SW and adjacentpins may be relatively small, and may generate current leakage failures.Further, the heat dissipation performance of switching pin SW in thisstructure may be relatively poor.

In one embodiment, an integrated circuit (IC) package assembly for aswitching regulator, can include: (i) a power switch chip including acontrol electrode and a first electrode on an obverse side and a secondelectrode on a reverse side, where the second electrode is configured asa switching terminal of a switching regulator; (ii) a control chipincluding a driving electrode and a plurality of input and outputelectrodes on the obverse side; (iii) a leadframe including an extensionpin, a substrate, and a plurality of discrete pins, where the extensionpin is formed integrally with the substrate, and where the reverse sideof the power switch chip is arranged on the substrate of the leadframeby a conductive material to electrically connect the second electrode tothe substrate; and (iv) the control electrode being electricallyconnected to the driving electrode, and the plurality of input andoutput electrodes of the control chip are electrically connected tocorresponding of the discrete pins.

Referring now to FIG. 3, shown is a diagram of a first example of anintegrated circuit package assembly for switching regulators, inaccordance with embodiments of the present invention. FIG. 4 shows asectional view of FIG. 3 along the line/path A-A′. Integrated circuitpackage assembly for switching regulators 10 can include leadframe 11,power switch chip 12, insulated isolation layer 13, control chip 14, andpackage encapsulant 15. For example, power switch chip 12 and controlchip 14 can be stacked on leadframe 11. Integrated circuit assembly 10can also include additional transistors or ICs. Further, substrate 112can be as large as possible in a range defined by the package volume, inorder to facilitate heat dissipation.

Leadframe 11 can include extension pin 111, substrate 112, and aplurality of discrete pins 113. Extension pin 111 can be integrallyformed with substrate 112, and may be located relatively far away fromdiscrete pins 113. For example, the space between extension pin 111 andadjacent discrete pins 113 may be at least as great as a space betweentwo adjacent discrete pins 113. In order to achieve the arrangement ofextension pin 111 relatively far away from discrete pins 113, discretepins 113 can be arranged on a first side (A′) and a second side (A),where the first and second sides that are opposite sides of thesubstrate. Also, the number of discrete pins 113 on the first side maybe greater than that on the second side, and the difference between thetwo sides can be no less than 2.

As shown in FIG. 3, the integrated circuit package assembly applied forthe switching regulator of FIG. 1 can include 5 pins. For example,leadframe 11 can include 4 discrete pins. For example, a first, asecond, and a third discrete pin 113 are arranged on a first side ofsubstrate 112, and the second discrete pin may be arranged between thefirst and the third discrete pins. The first and third discrete pins maybe arranged on or near the ends of the first side of substrate 112, andthe fourth discrete pin can be arranged on the second side opposite tothe first discrete pin (e.g., toward a left side of FIG. 3).

Extension pin 111 can be arranged on the second side of substrate 112,and may be relatively far away from the discrete pins on the secondside, which can extend outward from the second side. As shown in FIG. 3,extension pin 111 can be arranged opposite to third discrete pin 113,and the fourth discrete pin and extension pin 111 can be arranged on twoends of the second side of substrate 112. Therefore, the space betweenextension pin 111 and all discrete pins can be made as large aspossible, in order to avoid possible noise interference to adjacent pinsdue to spike or transient voltages. In addition, possible failure due tocurrent leakage can be substantially avoided with this approach.

For example, the first discrete pin can be a ground pin, the seconddiscrete pin can be a supply pin, a third discrete pin can be a voltagesensing pin, the fourth discrete pin can be a current sensing pin, andthe extension pin can be a switching pin. In one particular example,integrated circuit package assembly 10 shown in FIGS. 3 and 4 can bepackaged as SOT23-5 with advantages of relatively small volume and size.Integrated circuit package assembly 10 can address potential problems ofnoise interference and failure of current leakage of other SOT23-5packages. In one example application, integrated circuit packageassembly for switching regulators 10 can be employed for light-emittingdiode (LED) drivers to drive LED loads.

As described herein, and “electrode” can include a bonding pad, a“terminal” can be a circuit element connection or node, and a “pin” caninclude an external connection to the IC package assembly. As oneskilled in the art will recognize, the number of discrete pins ofintegrated circuit package assembly 10, as well as the arrangement ofextension pin 111 may not be limited to the above example. Rather, anyother available pin arrangements, whereby the extension pin can bearranged relatively far away from other discrete pins can also beutilised in particular embodiments.

Power switch chip 12 can include control electrode 121 and firstelectrode 122 on the obverse (e.g., top) side, as well as a secondelectrode on the reverse (e.g., bottom) side. The second electrode isnot shown in the drawings, but may be configured as a switching terminalof the integrated circuit package assembly for switching regulators. Theswitching terminal (e.g., SW) can be a common node between a powerswitch and an inductor of a power stage circuit of a switchingregulator. Generally, the second electrode of power switch chip 12configured as the switching terminal can be an electrode coupled to ahigh side of a voltage supply, and the first electrode of power switchchip 12 can be an electrode coupled to a low side (e.g., ground) of avoltage supply.

Power switch chip 12 can include any suitable transistors, such asMOSFET transistors or bipolar transistors. For example, controlelectrode 121 can be a gate of a power MOSFET transistor. When the typeof the power MOSFET transistor is N-type, the second electrode arrangedon the obverse side of power switch chip 12 and configured as theswitching terminal can be a drain, and electrode 122 can be a source.When the type of the power MOSFET transistor is P-type, the secondelectrode arranged on the obverse side of power switch chip 12 andconfigured as the switching terminal can be a source, and electrode 122can be a drain.

Control chip 14 can include driving electrode 141, and a plurality ofinput and output electrodes on the obverse side. In the example of FIG.3, electrode 122 of power switch chip 12 can connect one input andoutput electrode of control chip 14 by bonding wires to couple firstelectrode 122 to ground through control chip 14. Of course, when powerswitch chip 12 is not to be coupled to ground through control chip 14,driving electrode 141 of control chip 14 can be coupled to controlelectrode 121 of power switch chip 12, and first electrode 122 of powerswitch chip 12 can be coupled to a corresponding discrete pin.

The reverse side of power switch chip 12 can connect to substrate 112 ofleadframe 11 through a conductive material. Therefore, the secondelectrode configured as the switching terminal can be electricallycoupled to substrate 112. For example, power switch chip 12 can beconnected to substrate 112 by pasting a conductive adhesive, or by asoldering process. Extension pin 111 can be integrally formed withsubstrate 112. Therefore, the second electrode of power switch chip 12can connect to extension pin 111 without bonding wires, and theassociated resistance can be lower than bond wire connections wouldallow. In addition, the heat dissipation performance can be improved,and failure due to current leakage can be substantially avoided.

Control chip 14 can be stacked on power switch chip 12 through aninsulated isolation layer 13. Also, control electrode 121 and firstelectrode 122 on the obverse side of power switch chip 12 can be exposedwhen control chip 14 is arranged to connect to corresponding input andoutput electrodes of control chip 14 through bonding wires. Controlelectrode 121 of power switch chip 12 can connect to driving electrode141 through bonding wires. Also, the input and output electrodes ofcontrol chip 14 can be electrically coupled to corresponding discretepins 113 through bonding wires.

Package encapsulant 15 with a permittivity higher than a predeterminedvalue can be used to overlap and encapsulate control chip 14, powerswitch chip 12, and leadframe 11. Encapsulate 15 can also expose an endof pins from the package in order to accommodate electrical connectionbetween integrated circuit package 10 and external circuitry. Forexample, a higher permittivity of packaging 15 can improve theinsulation performance between the extension pin and discrete pins, inorder to substantially avoid possible failures due to current leakage.

Referring now to FIG. 5, shown is a diagram of a second example of anintegrated circuit package assembly for switching regulators, inaccordance with embodiments of the present invention. FIG. 6 shows asectional view diagram along the line/path A-A′ of the integratedcircuit package assembly for switching regulators of FIG. 5, inaccordance with embodiments of the present invention. In this particularexample, integrated circuit package assembly for switching regulators 20can include leadframe 21, power switch chip 22, insulated isolated layer23, control chip 24, and package encapsulant 25.

The integrated circuit package assembly for switching regulators 20 canfurther include additional transistors and/or ICs. In this example, thearrangement of leadframe 21 may be similar to that of the above example,and can include extension pin 211, substrate 212, and a plurality ofdiscrete pins 213. Extension pin 211 can be integrally formed withsubstrate 212, and may be relatively far away from discrete pins 213.The space between extension pin 211 and adjacent discrete pins 213 maybe at least as great as the space between two adjacent discrete pins213.

Control chip 24 can include driving electrode 241, and a plurality ofinput and output electrodes on the obverse side. Different from theabove example, control chip 24 may not be stacked on power switch chip22. Rather, both control chip 24 and power switch chip 22 can bearranged on leadframe 21. The reverse side of power switch chip 22 maybe pasted on substrate 212 by a conductive material, in order toelectrically connect the second electrode on the reverse side of powerswitch chip 22 to substrate 212. The reverse side of control chip 24 canbe pasted on substrate 212 by insulated isolation layer 23. Drivingelectrode 241 can be electrically connected to control electrode 221 ofpower switch chip 22 through bonding wires.

For example, first electrode 222 of power switch chip 22 can connect toone input/output electrode of control chip 24 through bonding wires toconnect electrode 222 to ground through control chip 24. This connectionmay be utilised when power switch chip 22 is to be coupled to groundthrough control chip 24. Otherwise, control electrode 241 of controlchip 24 can connect to driving electrode 221 of power switch chip 22.Also, first electrode 222 of power switch chip 22 can connect tocorresponding discrete pin through bonding wires.

In this example, extension pin 211 connected to the second electrodeconfigured as the switching terminal of the power switch chip can beintegrally formed with the substrate of the leadframe to improveinternal electrical connectivity, and the heat dissipation performanceof the package assembly. In addition, extension pin 211 can be arrangedrelatively far away from other discrete pins 213, in order to decreaseinterference to discrete pins by the extension pin, and to avoidpotential current leakage failures.

Referring now to FIG. 7, shown is a diagram of a third example of anintegrated circuit package assembly for switching regulators, inaccordance with embodiments of the present invention. FIG. 8 shows asectional view diagram along the line/path A-A′ of the integratedcircuit package assembly for switching regulators of FIG. 7, inaccordance with embodiments of the present invention. Integrated circuitpackage assembly 30 can include leadframe 31, power switch chip 32,insulated isolation layer 33, control chip 34, and package encapsulant35. For example, power switch chip 32 and control chip 34 can be stackedon leadframe 31. Integrated circuit assembly 30 can further includeother transistors and/or ICs.

Substrate 312 can be as large as possible in a range defined by thepackage volume, in order to facilitate heat dissipation. Leadframe 31can include a plurality of extension pins 311, substrate 312, and aplurality of discrete pins 313. A plurality of extension pins 311 can beintegrally formed with substrate 312, and may be arranged on a firstside (side of A) of substrate 312. A plurality of discrete pins 313 canbe arranged on a second side (side of A′) of substrate 312. Also, thesize of substrate 312 can be as large as possible within a scope asdetermined by the size of the package assembly.

For example, the number of extension pins 311 can be consistent with(e.g., the same as) that of discrete pins 313. For example, as shown inFIG. 7, leadframe 31 can include four extension pins and four discretepins that are arranged on opposite sides of substrate 312. Therefore,extension pins 311 can be relatively far away from discrete pins 313, inorder to avoid noise interference to adjacent pins generated by aspike/transition voltage, and to avoid potential current leakagefailures. In addition, extension pins can be integrally formed with thesubstrate in order to increase the area of the portions of pins exposedfrom the package assembly, to increase the area of heat dissipation toimprove heat dissipation performance.

For example, the integrated circuit package assembly 30 shown in FIGS. 7and 8 can be packaged as an SOT8 with eight pins. Four pins on the firstside can be configured as extension pins extending from the first sideof substrate 312, and four pins on the second side can be configured asdiscrete pins that are not connected to substrate 312. For example,integrated circuit package assembly 10 can be employed for LED driversto drive LED loads. Also, the number of discrete pins of integratedcircuit package assembly 30 and the arrangement of the extension pin canbe the same, or different numbers. Further, the extension pins and thediscrete pins can be arranged symmetrically, or asymmetrically in somecases.

Power switch chip 32 can include control electrode 321 and electrode 322on the obverse side, and a second electrode on the reverse side (whichis not shown in drawings and configured as a switching terminal of theintegrated circuit package assembly). The switching terminal can be acommon node between a power switch and an inductor of a power stagecircuit of a switching regulator. Generally, the second electrode ofpower switch chip 32 configured as the switching terminal can be anelectrode coupled to a high side of a voltage supply, and the firstelectrode of power switch chip 12 can be an electrode coupled to a lowside of a voltage supply.

Power switch chip 32 can be any suitable type of transistors, such asMOSFET transistors or bipolar transistors. Therefore, control electrode321 can be a gate of a power MOSFET transistor. When the type of thepower MOSFET transistor is N-type, the second electrode arranged on theobverse side of power switch chip 32 and configured as the switchingterminal can be a drain, and first electrode 322 can be a source. Whenthe type of the power MOSFET transistor is P-type, the second electrodearranged on the obverse side of power switch chip 32 and configured asthe switching terminal can be a source, and first electrode 322 can be adrain.

Control chip 34 can include driving electrode 341 and a plurality ofinput and output electrodes on the obverse side. In the example of FIG.7, electrode 322 of power switch chip 32 can connect one input/outputelectrode of control chip 34 by bonding wires to couple first electrode322 to ground through control chip 34. This particular connection can bearranged when power switch chip 32 should be coupled to ground throughcontrol chip 34. When power switch chip 32 is not to be coupled toground through control chip 34, driving electrode 341 of control chip 34can be coupled to control electrode 321 of power switch chip 32, andelectrode 322 of power switch chip 32 is coupled to a correspondingdiscrete pin.

The reverse side of power switch chip 32 can connect to substrate 312 ofleadframe 31 through a conductive material. Therefore, the secondelectrode configured as the switching terminal can electrically connectto substrate 312. For example, power switch chip 32 can be connected tosubstrate 312 by pasting a conductive adhesive, or by soldering process.Extension pin 311 can be integrally formed with substrate 312.Therefore, the second electrode of power switch chip 32 can connect toextension pin 311 without bonding wires, and the resistance can be loweras compared to bonding wire connections. Thus, heat dissipationperformance can be improved, and potential current leakage failures canbe substantially avoided.

Control chip 34 can be stacked on power switch chip 32 through insulatedisolation layer 33. Also control electrode 321 and first electrode 322on the obverse side of power switch chip 32 may be exposed when controlchip 34 is arranged to connect to corresponding input and outputelectrodes of control chip 34 through bonding wires. Control electrode321 of power switch chip 32 can connect to driving electrode 341 throughbonding wires. The input and output electrodes of control chip 34 can beelectrically connected to corresponding discrete pins 313 throughbonding wires.

Package encapsulant 35 with a permittivity higher than a predeterminedvalue can be configured to overlap and encapsulate control chip 34,power switch chip 32, and leadframe 31. Packaging encapsulant 35 canexpose the ends of pins to accommodate electrical connection betweenintegrated circuit package 10 and external circuits (e.g., aprinted-circuit board [PCB]). For example, a higher permittivity canimprove the insulation performance between the extension pin anddiscrete pins, in order to avoid potential failure due to currentleakage.

Referring now to FIG. 9, shown is a diagram of a fourth example of anintegrated circuit package assembly for switching regulators, inaccordance with embodiments of the present invention. Also, FIG. 10shows a sectional view diagram along the line/path A-A′ of theintegrated circuit package assembly for switching regulators of FIG. 9,in accordance with embodiments of the present invention.

Similar with the examples above, integrated circuit package assembly forswitching regulators 40 can include leadframe 41, power switch chip 42,insulated isolated layer 43, control chip 44, and package encapsulant45. Integrated circuit package assembly 40 can also include additionaltransistors and/or ICs. In this example, the arrangement of leadframe 41can include extension pin 411, substrate 412, and a plurality ofdiscrete pins 413. Extension pin 411 can be integrally formed withsubstrate 412, and may be relatively far away from discrete pins 413.The space between extension pin 411 and adjacent discrete pins 413 canbe at least as great as the space between two adjacent discrete pins413.

Control chip 44 can include driving electrode 441 and a plurality ofinput and output electrodes on the obverse side. In this example,control chip 44 may not be stacked on power switch chip 42. Rather, bothcontrol chip 44 and power switch chip 42 can be arranged on leadframe41. The reverse side of power switch chip 42 can be pasted on substrate412 by a conductive material to electrically connect the secondelectrode on the reverse side of power switch chip 42 to substrate 412.The reverse side of control chip 44 can be pasted on substrate 412 byinsulated isolation layer 43. Also, driving electrode 441 can beelectrically connected to control electrode 421 of power switch chip 42through bonding wires.

For example, first electrode 422 of power switch chip 42 can connect toone input/output electrode of control chip 44 through bonding wires toconnect first electrode 422 to ground through control chip 44. Thisconnection can be made when power switch chip 42 is to be coupled toground through control chip 44. Otherwise, control electrode 441 ofcontrol chip 44 can connect to driving electrode 421 of power switchchip 42. First electrode 422 of power switch chip 42 can connect tocorresponding discrete pin through bonding wires.

The embodiments were chosen and described in order to best explain theprinciples of the invention and its practical applications, to therebyenable others skilled in the art to best utilize the invention andvarious embodiments with modifications as are suited to particularuse(s) contemplated. It is intended that the scope of the invention bedefined by the claims appended hereto and their equivalents.

What is claimed is:
 1. An integrated circuit (IC) package assembly for aswitching regulator, comprising: a) a power switch chip comprising acontrol electrode and a first electrode on an obverse side and a secondelectrode on a reverse side, wherein said second electrode is configuredas a switching terminal of said switching regulator; b) a control chipcomprising a driving electrode and a plurality of input and outputelectrodes on said obverse side; c) a leadframe comprising an extensionpin, a substrate, and a plurality of discrete pins comprising first,second, third, and fourth discrete pins, wherein said extension pin is aswitching pin that is formed integrally with said substrate, and whereinsaid reverse side of said power switch chip is arranged on saidsubstrate of said leadframe by a conductive material to electricallyconnect said second electrode to said substrate, wherein said seconddiscrete pin is arranged between said first and third discrete pins on afirst side of said substrate that is opposite to a second side of saidsubstrate, said fourth discrete pin is arranged on said second sideopposite to said first discrete pin, and said extension pin is arrangedon said second side opposite to said third discrete pin; and d) saidcontrol electrode being electrically connected to said drivingelectrode, said first electrode being electrically connected to one ofsaid plurality of input and output electrodes, and each remaining ofsaid plurality of input and output electrodes of said control chip beingelectrically connected to corresponding of said plurality of discretepins, wherein a space between said extension pin and a nearest of saidplurality of discrete pins is greater than a width of said control chip.2. The IC package assembly of claim 1, wherein wire bond connectionsfrom each of said plurality of discrete pins are only to a correspondingelectrode on said control chip, and wherein every discrete pin that ispart of said leadframe is in said plurality of discrete pins.
 3. The ICpackage assembly of claim 1, wherein said control electrode comprises agate electrode, said first electrode comprises a source electrode, andsaid second electrode comprises a drain electrode.
 4. The IC packageassembly of claim 1, wherein said control electrode comprises a gateelectrode, said first electrode comprises a drain electrode, and saidsecond electrode comprises a source electrode.
 5. The IC packageassembly of claim 1, wherein said first discrete pin comprises a groundpin, said second discrete pin comprises a supply pin, said thirddiscrete pin comprises a voltage sensing pin, and said fourth discretepin comprises a current sensing pin.
 6. The IC package assembly of claim1, further comprising a package encapsulant that overlaps said controlchip, said power switch chip, and said leadframe.
 7. The IC packageassembly of claim 6, wherein a portion of each of said extension pin andsaid plurality of discrete pins are exposed from said packageencapsulant.
 8. The IC package assembly of claim 6, wherein apermittivity of said package encapsulant is higher than a predeterminedvalue.
 9. The IC package assembly of claim 1, wherein said reverse sideof said control chip is arranged on said power switch chip by aninsulated isolation layer.